09 Sputter Deposition

7/28/2019 09 Sputter Deposition

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Center for Materials for Information Technologyan NSF Materials Science and Engineering Center

Sputter Deposition

Lecture 9

G.J. Mankey

[email protected]


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Sputter Deposition

Magnetron sputtering is the most widely used method for

vacuum thin film deposition.

Although the basic diode sputtering method (without

magnetron or magnetic enhanced) is still used in some

application areas, magnetron sputtering now serves over 90%

of the market for sputter deposition.

Magnetron sputtering can be used to coat virtually anything

with a wide range of materials - any solid metal or alloy and a

variety of compounds.

ref: www.gencoa.com


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Sputtering System

A typical sputtering

system consists of a

vacuum chamber

with substrate

holders andmagnetron guns,

vacuum pumps and

gauging, a gas

supply system,

power supplies and a

computer control

system.ref: http://www.teercoatings.co.uk


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The Magnetron

A Magnetron is comprised of :

A CATHODE= electron source

An ANODE= electron collector

A combined ELECTRIC &MAGNETIC FIELD B X E

ref: www.gencoa.com


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The Plasma Discharge

Plasma is a fluid of positive ions

and electrons in a quasi-neutral

electrical state. The vessel that

contains this fluid is formed by

electric and magnetic fields.

In many plasma coating applications

positive ions are generated bycollisions between neutral particles

and energetic electrons. The

electrons in a plasma are highly

mobile, especially compared to the

larger ions (typically argon for

sputtering). Control of the highly mobile plasma

electrons is the key to all forms of

plasma control.ref: www.gencoa.com


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Microscopic View of Sputtering The impact of an atom or ion on a surface produces

sputtering from the surface as a result of themomentum transfer from the incoming particle. Unlike

many other vapor phase techniques there is no melting

of the material.

History of Sputtering

The verb to SPUTTER originates from Latin SPUTARE(To

emit saliva with noise).

Phenomenon first described 150 years ago ...

Grove (1852) and plcker (1858) first reported vaporization

and film formation of metal films by sputtering.

Key for understanding discovery of electrons and positive

ions in low pressure gas discharges and atom structure (J.J.

Thomson, Rutherford), 1897-- Other names for SPUTTERING were SPLUTTERING and

CATHODE DESINTEGRATION.

ref: www.gencoa.com


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The Magnetron Gun

A magnetron consists of a target with magnets arranged

behind it to make a magnetic trap for charged particles, such

as argon ions, in front of the target.

Atoms are knocked out of the target surface by the ions - this

is sputtering. These sputtered atoms arent charged

negatively or positively, so they go straight out of the

magnetic trap to coat the substrate.ref: http://www.teercoatings.co.uk


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The Magnetron Plasma

Confinement between a negatively biased target and closed magnetic

field produces a dense plasma. High densities of ions are generated within the confined plasma, and

these ions are subsequently attracted to the negatively biased target,

producing sputtering at high rates.ref: www.gencoa.com


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Target Erosion

Target erosion is greatest where the magnetic field and the subsequent

plasma density is greatest. This leads to inefficient use of target material, particularly in the case

of ferromagnetic targets.

ref: www.gencoa.com


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Sputtering Insulators

For an insulator target, the ions bombarding the target will create

charging, and the electric field necessary to maintain a plasma is

greatly diminished.

To alleviate this problem, an RF power supply is used to generate

the electric field.

ref: www.gencoa.com


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Magnetron Guns

ref: www.lesker.com


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The Latest in UHV Sputtering

A UHV, magnetron sputter source that fits through the port of a 2.75" CF flange

complete with its tilt gimbals assembly.

The AJA International new A310-XP only needs a 2.75" CF to accommodate the

source head, tilt gimbals and gas injection/isolation chimney.

This revolutionary new design is true UHV - all ceramic to metal construction.

http://www.ajaint.com

09 Sputter Deposition

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